Phyllis Schlafly, the conservative activist who almost single-handedly helped defeat the proposed Equal Rights Amendment in the 1970s and pushed the Republican Party to the right in ensuing decades, has died. She was 92.

Schlafly died Monday of cancer at her home in St. Louis, her son John Schlafly said.

Known as "the first lady of anti-feminism," Schlafly rose to national attention in 1964 with her self-published book, “A Choice Not an Echo,” that became a manifesto for the far right. The book, which sold 3 million copies, chronicled the history of the Republican National Convention and is credited with helping conservative Senator Barry Goldwater of Arizona win the 1964 GOP nomination.

She later helped lead opposition to the ERA, a proposed constitutional amendment that would guarantee equal rights under the law regardless of gender. Schlafly argued that the measure would mean the end of the traditional family.

Supporters of the measure argued it would require that laws determining child support and job opportunities be designed without regard to gender.

Schlafly told the Associated Press in 2007 that perhaps her greatest legacy was the Eagle Forum, which she founded in 1972. The ultraconservative group has chapters in several states and claims 80,000 members. "I've taught literally millions of people how to participate in self-government,'' Schlafly said.

The Eagle Forum pushes for low taxes, a strong military and English-only education. The group is against efforts it says are pushed by radical feminists or encroach on U.S. sovereignty, such as guest worker visas. The group's website describes the Equal Rights Amendment as having had a "hidden agenda of tax-funded abortions and same-sex marriages.''

Saint Louis University history professor Donald Critchlow, who profiled Schlafly in his 2005 book, “Phyllis Schlafly and Grassroots Conservatism: A Woman's Crusade,” said the defeat of the amendment helped revive conservatism and pave the way for Ronald Reagan’s election in 1980.

Schlafly remained active in conservative politics well into her 80s, when she was still writing a column that appeared in 100 newspapers, doing radio commentaries on more than 460 stations, and publishing a monthly newsletter.